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Topic: 1D X "Limitations" Fixable? (Read 29138 times)

Would somebody care to explain to me what this "f/8 AF limitation" is, please?

Does it mean autofocus won't work if you set your aperture smaller than f/8?

No, it just means that if your lens largest aperture is smaller than f/5.6 (next step is f/8 typically) it can't autofocus. Focusing is always made at largest aperture, the lens is stopped down to the target aperture when taking the picture.

Lenses don't have as small as f/8 natively, but with teleconverters you get it, 1.4x adds one stop, 2x two. So if your camera cannot do f/8 autofocus you cannot get autofocus with a 2x teleconverter on an f/4 lens or 1.4x on an f/5.6 lens, which can be a limitation for especially wildlife photography. 2x on 500/4 to get 1000/8 with autofocus can be a nice option to have. Or on the low end 400/5.6 => 560/8.

hi, agree here HDMI out would be awesome (and D4 a nonstarter), and abit dissapointed 1dx has no 5x10x zoom - its the best feature for canons with manual lenses (even for photos). cmon canon stop slacking!

In fact I use the Kenko DG that you have. I've taped the pins to prevent the lens reporting anything back to the camera. It has made me totally convinced that the limitations in f/no auto-focus performance is an artificial situation entirely created by Canon for reasons only they know.

Would somebody care to explain to me what this "f/8 AF limitation" is, please?

Does it mean autofocus won't work if you set your aperture smaller than f/8?

No, it just means that if your lens largest aperture is smaller than f/5.6 (next step is f/8 typically) it can't autofocus. Focusing is always made at largest aperture, the lens is stopped down to the target aperture when taking the picture.

Lenses don't have as small as f/8 natively, but with teleconverters you get it, 1.4x adds one stop, 2x two. So if your camera cannot do f/8 autofocus you cannot get autofocus with a 2x teleconverter on an f/4 lens or 1.4x on an f/5.6 lens, which can be a limitation for especially wildlife photography. 2x on 500/4 to get 1000/8 with autofocus can be a nice option to have. Or on the low end 400/5.6 => 560/8.

Excellent explanation. Thank you! I know understand and see what the problem could be. My f/2.8 lens would not have an issue, but an f/5.6 lens with a 2x teleconverter would. Not being able to use AF at that point would rather suck.Thanks, understood and filed.

an f/5.6 lens with a 2x teleconverter would. Not being able to use AF at that point would rather suck.

Actually, an f/5.6 lens with a 1.4x or an f/4 lens with a 2x would be f/8. It's not as bad as it sounds for most people - if you put a TC on an 'affordable' long lens (2x on 300/4 IS, 1.4x on 400/5.6 or 100-400), the IQ takes a substantial hit, resulting in a pretty soft image. Those most affected are people using supertele lenses, e.g. the 500/4 or 600/4 + 2x, or the 800/5.6 + 1.4x (I've run into birders with the latter). Most people doing that are shooting 1D-series bodies, so they're taking a double hit - loss of 1.3x crop and loss of f/8 AF.

No, it just means that if your lens largest aperture is smaller than f/5.6 (next step is f/8 typically) it can't autofocus. Focusing is always made at largest aperture, the lens is stopped down to the target aperture when taking the picture.

Lenses don't have as small as f/8 natively, but with teleconverters you get it, 1.4x adds one stop, 2x two. So if your camera cannot do f/8 autofocus you cannot get autofocus with a 2x teleconverter on an f/4 lens or 1.4x on an f/5.6 lens, which can be a limitation for especially wildlife photography. 2x on 500/4 to get 1000/8 with autofocus can be a nice option to have. Or on the low end 400/5.6 => 560/8.

It seems what torger implies really IS the point.I should think there would be a good number of sports, wildlife, et c., professionals who have long, relatively-fast lenses, but occasionally find themselves in a situation where they need that extra reach. Putting a 2x converter on an f:4 lens brings one to that point and, with depth-of-field being so narrow at 800, 1000 or 1200mm, that autofucus is virtually essential, particularly given that the viewfinder image at f:8 is not going to be bright.It seems there would be even more photographers who'd be likely buyers for this camera that possess lenses of modest apertures, but sometimes find themselves in situations where they'd like that 1.4 or 2x "boost", as well as those who don't always carry their big glass around. I certainly hope that Canon will fix the "Achilles heel" for what otherwise appears to be a stellar camera. Autofocusing at f:8, even if only in the center spot, has been a given for 1D series users for a decade now. Taking it back seems such a step in the wrong direction and gives us one less reason why these bodies are our first choice.

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1D series bodies (x4), L glass (x9)

baldusi

I can't believe nobody said the obvious ones:-custom Low and High limits on Auto-ISO.-More than 2EV for bracket shooting.-More than three shots for bracket shooting.-Prioritize Auto-ISO vs shutter in Av and Auto-ISO vs aperture in Tv (i.e. first play the iso within a range, then move the shutter speed or aperture depending on mode). In particular, variable light in sports could use this feature.-Block delete of images.-ExFAT support. May be even some other nice filesystems for the CF cards?-When doing LiveView Zoom, focus to zoomed part.-Voice notes for picture. Voice Notes and Tag notes for picture sets.-Be able to program a straight button for mirror lock up, for example.-Do time lapse with bracket shots.

All those, and everything that MagicLanter does could be very easily added in firmware. Let's not focus only on the f/8 issue (which might not be doable by firmware).

I certainly hope that Canon will fix the "Achilles heel" for what otherwise appears to be a stellar camera. Autofocusing at f:8, even if only in the center spot, has been a given for 1D series users for a decade now. Taking it back seems such a step in the wrong direction and gives us one less reason why these bodies are our first choice.

Well, overall I think it is a stellar camera. I agree with the previous comment that the lack of f/8 AF is a real issue for only a very small percentage users. (Dare I say it, perhaps more people are complaining about this issue online than there are current 1-series users who would be directly impacted?)

As discussed, they may not be able to 'fix it' for technical reasons. Consider - previous 1-series have a center point that's an f/4 line crossed with an f/8 line. The 1D X will have a dual f/2.8 and f/5.6 cross. It may be that Canon's lines differ from Nikon's - I know Canon uses 48-bit lines of all the same length, but different separation relative to the baseline (wider spacing for f/2.8 than f/5.6). The exception to that is the previous 1-series, where the lines for the center AF point are closer together (f/4 and f/8 spacing), but the lines are shorter so the higher pixel density regains the accuracy lost to the shorter baseline. That may not have been possible in the new sensor with its higher level of complexity. I don't know what the sensor lines for Nikon are like, but it may be that they have been using higher density AF Lines all along. Thus, Nikon's f/5.6 points might be more accurate than Canon's f/5.6 points, and that greater accuracy might allow them to work better at apertures narrower than f/5.6.

It may also depend on exactly why Canon chose to eliminate the f/8 capability. If it was for marketing rather than technical reasons, they may be setting the stage for a future pro-level crop body, such as a 14-16 MP APS-C, with substantial IQ improvements, where they'll bring back an f/8 capability, expanded to multiple points.

...they lock out the AF narrower than f/5.6 for a reason - likely because AF at f/8 with an f/5.6 sensor doesn't meet their standards. Still, they might be able to adjust the AF algorithms to deliver acceptable performance...

I buy this because of the bolded words above and below.

Now take a look of what Chuck Westfall said in another interview: "...Canon felt that while it would have been nice to preserve AF at f/8, the overall improvement in AF achieved with the 1D x took precedence... The improved algorithm means that AF won’t jump to the background as quickly, won’t be tripped up as easily by obstacles in front of the subject, and will handle subjects that are small in the frame much better... There are a lot of trade-offs in life, and this is one of them. Essentially, Canon Inc. decided that the overall improvement of the new 61-point AF system compared to the older 45-point system took precedence over the need for that particular feature..."

The AF sensor might not be able to provide enough data for the current algorithm to achieve what Westfall emphasizes as better performance. But an algorithm can calculate (based on enough data) as well as predict / guess / project / calculate-with-AI (based on insufficient data).

Since Canon never officially (right???) declares that 1D X is unable to AF with max f/8 or narrower lenses and there have been months for them to get feedback since last year's 1D X announcement, it's not hard to guess they are currently working on a better algorithm, especially if D4 can do it regardless of how.

Yes, I suppose that one of the upsides (aside from preserving speed and accuracy by limiting it to twice the light available at f/8) is that the slice of DOF used allowing more precision in the selection of targets - that seems to be the message here. Makes perfect sense.

However, I still think that this ought to be a user choice. Tweak it for performance at f/5.6 and above if wanted, but there ought to be a fall-back algorithm for f/8.

I can't believe nobody said the obvious ones:-custom Low and High limits on Auto-ISO.-More than 2EV for bracket shooting.-More than three shots for bracket shooting.-Prioritize Auto-ISO vs shutter in Av and Auto-ISO vs aperture in Tv (i.e. first play the iso within a range, then move the shutter speed or aperture depending on mode). In particular, variable light in sports could use this feature.-Block delete of images.-ExFAT support. May be even some other nice filesystems for the CF cards?-When doing LiveView Zoom, focus to zoomed part.-Voice notes for picture. Voice Notes and Tag notes for picture sets.-Be able to program a straight button for mirror lock up, for example.-Do time lapse with bracket shots.

All those, and everything that MagicLantern does could be very easily added in firmware. Let's not focus only on the f/8 issue (which might not be doable by firmware).

+1Thanks for jolting us out of the f/8 thing. Your points are well observed, relevant ones.

Yes, I suppose that one of the upsides (aside from preserving speed and accuracy by limiting it to twice the light available at f/8) is that the slice of DOF used allowing more precision in the selection of targets - that seems to be the message here. Makes perfect sense.

However, I still think that this ought to be a user choice. Tweak it for performance at f/5.6 and above if wanted, but there ought to be a fall-back algorithm for f/8.

Thanks, too, to the earlier poster for finding that quote. It makes great sense, considering who would be the primary buyers for this camera.However, I'm in Edwin Herdman's camp in thinking this is something that should be a choice, perhaps a Custom Function where the high performance focusing would be the default mode, with the f:8 algorithm a user selectable fall-back.

rlp

Why have a camera that does not auto focus with the new 2x EF Extender III and the new 500 & 600 f/4? As a life long Canon user I am extremely disappointed. I don't need or want video in my SLR, give me a GREAT SLR not some hybrid that does nothing well.